The analysis of solid samples can often be a difficult problem for the researchers dealing with infrared spectroscopy. In conventional absorption spectroscopy the measurement of absorption is transferred to a measurement of the radiation transmitted through the sample. On the contrary, in photoacoustic spectroscopy (PAS), the adsorbed radiation is determined directly via its heat and hence the sound produced in the sample. Fourier transform infrared PAS (FT-IR/PAS) is one of the main IR techniques which successfully can be applied in catalysis research. Examples of this spectroscopic technique application will be presented as well as some limits of its use. (c) 2007 Elsevier B.V. All rights reserved.